Pipelines that carry fluids, for example, petroleum, natural gas, multi-phase fluids or other fluids, are internally inspected or cleaned by inserting a pig into the pipeline at a first point. The fluids flowing through the pipeline push the pig through the pipeline to a second point where the pig is caught and removed from the pipeline. A pipeline pig can be any structure or device that can move through a pipeline to perform a function. In one example, a pipeline pig can be implemented as a pipeline scraper to clean an interior of the pipeline. In another example, a pipeline pig can be implemented to swab, i.e., remove liquids or gases, from the pipeline. In a further example, a pipeline pig can be implemented to batch, i.e., separate different fluids in the pipeline. In additional examples, pipeline pigs can be implemented to perform intelligent operations such as monitoring and conveying information about a particular condition or performance of the pipeline.
Pipeline pigs can be launched into pipelines by providing launch stations or catcher stations (or both) at multiple points along the pipeline at which a pipeline pig will be inserted or removed (or both). The insertion and retrieval of pipeline pigs can be performed manually (for example, with human operators) or with partial assistance for example, using electromechanical lifting, pushing and retrieving devices. Such devices perform high-level operations such as pig lifting, pushing, pulling or combinations of them while human operators perform finer operations such as positioning the pig for either launching or receiving.